Impingement-type separator



n5 aw Oct. 18, 1960 s. H. s. RAUB ETAL IMPINGEMENT TYPE SEPARATOR 2Sheets-Sheet 1 Filed May 24, 1957 INVENTORS WILLIAM M. GAYLORD,JR.SAMUEL H. S. RZUB ATTORNEY Oct. 18, 1960 s. H. s. RAUB EAL 2,956,641

IMFINGEMENT TYPE SEPARATOR Filed May 24, 1957 2 Sheets-Sheet 2 zag iINVENTORS WlLLlAM M. GAYLORD,JR. SAMUEL H. S. RAUB A 7' TORNE V2,956,641 IMPINGEMENT-TYPE SEPARATOR Samuel H. S. Ranb, Bay Village, andWilliam M. Gaylord, Jr., Shaker Heights, Ohio, assignors to UnionCarbide Corporation, a corporation of New York Filed May 24, 1957, Ser;No. 651,450

11 'Claims. (Cl. 183-410) This invention relates to impingement-typeseparators and more particularly to impingement-type separators for theremoval of finely divided matter from a gas stream.

One disadvantage of the heretofore known impingementtype separators isthe difficulty and expense of assembly. This problem is magnified ifirregularly shaped impingement members, such as the highly etlicientstreamlined tear-drop type, are used. This is because there are no flatsurfaces to secure tightly even though a rigid support system isessential. If the impingement members are loosely secured, they willrattle and vibrate when exposed to the impingement action of a highvelocity gas stream. More importantly, if the impingement member is madeof relatively low strength material, such as graphite or carbon, therattling and excessive vibration will cause stress fatigue and eventualbreakage. Also, with irregularly shaped members it is generallypreferable to retain such members in a certain position rela tive to theimpinging gas stream so as to achieve maximum separation efiiciency.This relationship cannot be maintained if the impingement members arenot rigidly supported and are allowed to move laterally in theirmountings.

Another problem ever present in the prior an impingement-type separatorsis the difficulty of cleaning such separators; that is, removing thefinely divided matter deposited in the separator but not dischargedthrough the drain hole. Such matter must be periodically removed fromthe separator to avoid excessive reentrainment and loss of separationefficiency. The cleaning problem of impingement separators poses aspecial problem because the separators are usually placed in staggeredrows to achieve maximum separator efliciency, and it is essentiallyimpossible to contact each impingement member with'a single cleaningtool such as a brush. In some cases this problem may be solved by use ofa cleaning fluid, but in certain applications a suitable cleaning fluidwould have a detrimental eifect on the impingement members andmechanical cleaning means must be used.

A still further unsolved problem facing the prior art is a method ofsecuring non-metallic impingement members in the separator casing. Ifthe gas stream is acidic, it may be necessary to use a non-metallicchemically inert material such as resin impregnated carbon or graphiteto avoid corrosion of the impingement members. In such case, a metalbond is of course unsuitable and a cement joint is to be avoided forease of disassembly and low cost.

One object of the present invention is to provide a high efiiciencyimpingement-type separator which is relatively easy and economical toassemble.

Another object of the present invention is to provide a high efficiencyimpingement-type separator which can be easily cleaned withoutdetrimentally affecting the impingemeht members.

A still further object is to provide a suitable method of securingnon-metallic impingement members in the separator casing;

res Patent These and other objects and advantages of this invention willbe apparent from the following description and accompanying drawings.

The impingement-type separator of the present invention comprises aseries of struts positioned normal to the direction of the gas streamflow at substantially uniform intervals across the cross-sectional areaof the separator and along the longitudinal flow path of the gas streamso that matter entrained in the gas stream is separated therefrom byimpingement against the struts. A series of removable retainersadjacently positioned to each other are provided, such retainers havingrecesses to hold the opposite ends of the struts in position. Therecesses are preferably contoured so that each strut end fits inconnecting recesses of adjacent retainers. For example, if asubstantially streamlined tear-drop strut is used, the connectingrecesses of adjacent retainers are shaped so that the combined contouris a tear-drop shape corresponding to the cross-sectional shape of thestruts.

The separator of this invention may be incorporated in either acylindrical or a rectangular casing, depending on the requirements ofthe particular application. For example, if the gas flow rate andquantity of finely divided matter entrained therein are relatively lowand a cylindrical casing is tobe used, the retainers are preferablyremovable rings extending around theinner circumference of the casing,and adja'cently stacked along the casing wall from the inlet to' thedischarge end. If the cross-sectional-are'a of the casing is relativelylarge, the retainers are preferably a'serieso-f flat strips across thetop and bottom of the casing. In the latter case, the struts and stripsare assembled in modules which are stacked or adjacently positioned toone another in the separator casing. This type of construction permitsthe use of relatively short struts in large size separators, which isadvantageous because it minimizes re-entrainment of separated matter inthe gas stream. Also, short struts are stronger and less likely to breakfrom stress fatigue.

The apparatus of'this invention may be easily assembled by firstslidably fixingthe ends of each strut in the recesses of the retainers,and then inserting a group or stack of the strut-retainer 'ass'embliesinthe separator casing. One'or both of the'en'ds of the'casing may then besealed to hold the'stack in position. lf'the module construction isused, each module may be separately assembled prior to placement in theseparator casing. Also, this type of construction facilitates rapid andeasy removal of the strut-retainer assemblies from the separator casingfor cleaning. This may be accomplished by simply breakingthe end seal.The invention also provides a reliable-method of securmg non-metallicimpingement members in the casing by slidably fixing the strut ends inthe contoured recesses of the retainers.

In the accompanying drawings:

Fig. l is a vertical longitudinal section of a cylindricalimpingement-type separate: embodying one form of the present invention;

Fig. 2 is a vertical transverse section of the same cylindricalimpingement-type separator taken along line 22 of Fig. 1;

Fig. 3 is a fragmentary lioriiontal section on an enlarged scale of thestrut-retainer recess assembly of the same cylindrical impingement-typeseparator taken along line 3-3 of Fig. 1;

Fig. 4 is a vertical longitudinal and partial crosssectional view of amodule assembly embodying another form of the present invention;

Fig. 5 is an end view of the same module assembly of Fig.4;

Fig. 6 is a top plan view of the same module assembly of Fig. 4; and

Fig. 7 is a top plan view of an alternate module assembly.

Referring more specifically to Fig. 1, a gas stream containing finelydivided matter such as particles, droplets of a liquid, or dustsuspended in'droplets enters the separator 10 at the inlet end 11 of thecylindrical casing 12 and impinges against struts 13, which preferablyhave a substantially streamlined tear-drop cross-sectional shape. By thecombination of impingement and what is believed to be venturi(constricting) action, the finely divided matter is removed from the gasstream and passes into the collector 14 so that the gas emerging throughthe discharge end 15 is substantially cleaned of the finely dividedmatter. The deposited matter is discharged from the collector 14 throughconduits 16. The struts 13 are preferably retained in staggered rows toinsure intimate contact with the circulating gas, and thus achieve highseparation efiiciency. Also, a substantially streamlined tear-dropcross-section is preferred as the strut configuration since it provideshigh separation efliciency and minimum re-entrainment with minimumpressure drop because of the relatively smooth contact surfaces. Lowpressure drop through the separator is important to minimize therequired gas compression and resultant power costs. The struts 13 arepreferably positioned in the casing 12 in a direction normal to the gasflow, this relationship also contributing to high separation efiiciency.The struts 13 are also spaced at substantially uniform intervals alongthe longitudinal flow path of the gas for the same reason. Theindividual struts are held in ring retainers 17, the strut-retainerassemblies being stacked inside the casing 12 and held against theridges 18 on the inlet end, and by the pin 19 which is tack cemented inan angular hole 20 drilled through the discharge end retainer 17a intothe casing 12. The separator 10 and collector 14 are separated by agasket 20a, and the separator-collector assembly may be mounted betweenthe faces of standard flanges (not shown), with tie rods between suchflanges to hold the assembly together and provide gas-tight connections.

The separator-collector assembly is preferably vertically positionedwith the inlet end 11 at the top and the discharge end 15 at the bottom.Also, the tear-drop struts should be positioned with their major axis inthe vertical direction. It can be seen that the struts 13 may be easilyand quickly removed for cleaning by removing the tie rods, breaking thetack cement joint holding the pin 19 in hole 20, and removing thestrut-retainer assemblies from the casing 12. It will also be apparentthat this construction facilitates quick and easy reassembly.

Fig. 2 illustrates the cross-section of a strut-ring retainer assemblywithin the separator casing 12. The struts 13 are preferably positionednormal to the gas flow at substantially uniform intervals across thecrosssectional area of the separator casing 12 to obtain uniformly highseparation efliciency for all the gas passing through the casing. Thestruts 13 are slidably mounted in recesses 21 of the ring retainers 17.

Fig. 3 shows details of the strut-retainer assembly wherein the ends ofthe substantially tear-drop shaped struts are slidably mounted inconnecting contoured recesses 21 in adjacent retainers 17. It is to benoted that the cross-section of the illustrated struts is not a perfectstreamlined tear-drop shape. This is becauseof the high cost ofmachining such perfect shapes and the high separation efliciency of thecheaper, non-perfect tear-drop shapes. Consequently, the phrasetear-drop shape, as employed herein, includes such non-perfect tear-dropshapes. The struts are positioned with their major diameterssubstantially parallel to the gas flow. As can be seen, the front partof the strut fits in the retainer nearer the inlet end of the separator,,whereas the back part of the strut fits in the adjacent retainer nearerthe separated matter.

4 discharge end. Since in the preferred embodiment the connectingrecesses of the adjacent retainers are contoured to form atear-drop-shape, the strut fits tightly in the recesses and impingementby the gas stream does not produce lateral or vertical movement of thestrut. The struts are preferably assembled in staggered rows for theaforementioned reasons. Also, the struts are arranged with sufiicientclearance between adjacent members so that clogging by deposited matteris avoided. However, the staggered row construction still insuresintimate contact between the circulating gas stream and the struts, andtogether with the preferred tear-drop crosssectional shape, provides ahighly eflicient apparatus for removal of the finely divided matter fromthe gas stream.

This method of holding the struts in the casing is particularlyadvantageous when the fluids processed require the use of a non-metallicchemically inert material such as resin-impregnated graphite. Since thejoint between the struts and the retainer is mechanical, possiblecorrosion of bonding material is avoided. Also as previously discussed,it would be impossible to use a metal bonding method for a graphitejoint, and a cement joint is undesirable for case of disassembly and lowcost.

Figs. 4-6 illustrate a module assembly comprising a series of internalstruts and separate strut retainer means, which could be adopted forinsertion in cylindrical casing 12 (see Fig. l) or a rectangular casing.It has been found that the separation efficiency of the ring retainerassembly of Figs. 1-3 decreases when relatively large diameter units,e.g. 24 inches, are used. This is caused by a combination ofre-entrainment and inability to drain the deposited matter from theseparator at a sufliciently high rate. When relatively large diameterseparators and long struts are used, an extremely large quantity offinely divided matter is deposited on the walls of the struts due to thelarge strut impingement surface, and this matter flows down such wallsto the collector and drain connection. Due to the long flow path of suchdeposited matter, some of it is re-entrained by the circulating gasstream. Also, the matter reaching the collector section tends to buildup at the drain connection. Again, part of this buildup may bere-entrained in the circulating gas stream. Additional disadvantages ofrelatively long struts are high manufacturing costs and the possibilityof breakage. A high velocity gas stream establishes lateral vibration ifthe struts are too long, and this may cause stress fatigue and breakage.

These problems have been solved by using relatively short struts, andretaining the ends of such struts in recesses of strips so as to formmodule units. Any desired number of modules may be adjacently positionedto each other in the separator casing so as to process any desiredquantity of gas without excess re-entrainment of This is possiblebecause the module units may be stacked one on top of the other whilestill retaining relatively short struts, and draining the depositedmatter from each module unit through a common drain conduit to a drainopening in the bottom module.

Referring more specifically to Figs. 4-6, the components which aresimilar to those shown in other figures are designated by similarreference numerals. The gas stream entering module impinges against thesubstantially tear-drop shaped struts 113 which are positioned andbounded by a series of strip retainers 117 bonded to each other acrossthe top and bottom of the module unit, and extending from the inlet endto the discharge end of such unit. The collector 114 communicates withthe discharge end of the module unit 110, and includes discharge sheets122 which are bonded to the top and bottom discharge end retainers 117a.The deposited matter is drained through drain opening 123 in the bottomdischarge sheet 122. Also, if another module unit is stacked on top ofmodule 110, the finely divided matter deposited therein is drained intoan opening 124 in the top discharge sheet 122. The drained matter passesdownwardly through conduit 126 which communicates with bottom opening123, and is'discharged therethrough. It can thus be seen that the moduleconstruction prdvid'e'sa method of minimizing re-entrainment of finelydivided matter in the circulating gas stream.

The present invention also provides a convenient and eflicient method ofassembling a group of modules for insertion in the separator casing.First, each module is assembled by inserting the struts 113 in theconnecting recesses 121 of adjacent strip retainers 117. Next, theindividual modules are assembled together by, for example, placing onemodule on top of another so that a group of module locking struts 127which have been assembled so as to telescope above the top stripretainers 117 fit in the corresponding recesses of the bottom stripretainers 117 of the top module. In this manner the modules may be heldtogether and vertically aligned so that the bottom drain opening 123 ofthe top module is directly centered over the top drain opening 124 ofthe bottom module. Also adjoining side recesses 128 are provided on theopposite ends of the adjacent strip retainers 117 so that struts 113 maybe placed between two modules positioned side-by-side. This isaccomplished by contouring the strip ends so that the adjoining recessesof two adjacent strips of a given module form one-half of the tear-dropcontour along the major axis of the tear drop.

Fig. 7 illustrates an alternate module assembly wherein the stripretainers 217 are assembled parallel instead of normal to the gas flow,as in Fig. 6. Instead of the retainer recesses joining across the widthof the tear-drop shape, as in the other figures, the recesses 221 ofFig. 7 join across the length or major diameter of the tear-drop shape,and the struts 213 fit therebetween.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures described. It should be recognized that various modificationsare possible. For example, instead of the preferred streamlinedtear-drop cross-sectional shape, the impingement members could be the Vtype of bent sheets or any other conventional shape.

What is claimed is:

1. In an impingement-type separator for the removal of finely dividedmatter from a gas stream, means for separating such matter comprising aseries of struts having a curved cross-sectional shape and beingpositioned normal to the direction of the gas stream flow atsubstantially uniform intervals across the cross-sectional area of theseparator and along the longitudinal flow path of said gas stream sothat matter entrained in the gas stream is separated therefrom byimpingement against said struts, and means for holding the struts insuch position comprising a series of removable retainers adjacentlypositioned to each other, said retainers having recesses to holdopposite ends of said struts in position, being arranged and constructedwith pairs of recesses in adjacent retainers connecting with each otherand contoured to each receive a section of the strut end.

2. An impingement-type separator for the removal of finely dividedmatter from a gas stream according to claim 1, in which said struts havea tear-drop crosssectional shape and are positioned with their majordiameters substantially parallel to the gas flow direction.

3. An impingement-type separator for the removal of finely dividedmatter from a gas stream according to claim 1, in which the combinedcontour of such connecting recess pairs corresponds to thecross-sectional shape of the struts.

4. An impingement-type separator for the removal of finely dividedmatter from a gas stream according to claim 1, in which said struts havea tear-drop cross sectional shape, and the combined contour of such con-8 necting recess pairs is a tear-drop shape corresponding to the cro's'ssectional shape of the struts.

5. An impingement-type separator for the removal of finely dividedmatter from a gas stream according to claim 1, in which said struts havea tear-drop crosssectional shape and are positioned with their majordiameters substantially parallel to the gas flow; and thecombinedcontour of such connecting recess pairs is a tear-drop shapecorresponding to the cross-sectional shape of the struts.

6. An impingement-type separator for the removal of finely dividedmatter from a gas stream comprising a cylindrical casing having a gasinlet end and a gas discharge end; a series of internal struts having acurved cross-sectional shape and being positioned normal to the flowdirection of said gas stream at substantially uniform intervals acrossthe cross-sectional area of the casing and along the longitudinal flowpath of said gas stream so that matter entrained in the gas stream isseparated therefrom by impingement against such struts; and a series ofremovable rings adjacently positioned to each other and extending fromthe inlet end to the discharge end of said casing, said rings havingrecesses to hold opposite ends of the struts in position and beingarranged and constructed with pairs of recesses in adjacent retainersconnecting with each other and contoured to each receive a section ofthe strut end.

7. An impingement-type separator for the removal of finely dividedmatter from a gas stream according to claim 6, in which said struts havea tear-drop crosssectional shape and are positioned with their majordiameters substantially parallel to the gas flow direction.

8. An impingement-type separator for the removal of finely dividedmatter from a gas stream comprising a casing having a gas inlet end anda gas discharge end; a series of internal struts having a curvedcross-sectional shape and being positioned normal to the flow directionof said gas stream at substantially uniform intervals across thecross-sectional area of the casing and along the longitudinal flow pathof said gas stream so that matter entrained in the gas stream isseparated therefrom by impingement against such struts; and strutretainer means comprising a series of adjacent strips positioned acrossthe top and bottom of the casing and extending from the inlet to thedischarge end of said casing, such retainer means having recesses tohold opposite ends of the struts in position being arranged andconstructed with pairs of such recesses in adjacent strips connectingwith each other and contoured to each receive a section of the strutend.

9. An irnpingement-type separator for the removal of finely dividedmatter from a gas stream according to claim 8, in which said struts havea tear-drop crosssectional shape, and the combined contour of suchconnecting recess pairs is a tear-drop shape corresponding to thecross-sectional shape of the struts.

10. An impingement-type separator for the removal of finely dividedmatter from a gas stream comprising a cylindrical casing having gasinlet and gas discharge ends; a series of internal struts having atear-drop crosssectional shape positioned normal to the flow directionof said gas stream at substantially uniform intervals across thecross-sectional area of the casing and along the longitudinal flow pathof said gas stream so that matter entrained in the gas stream isseparated therefrom by impingement against such struts; and a series ofremovable rings adjacently positioned to each other and extending fromthe inlet end to the discharge end of said casing, said rings havingrecesses to hold opposite ends of the struts in position, and beingarranged and constructed with pairs of such recesses in adjacent ringsconnecting with each other and jointly forming a tear-drop shapedcontour corresponding to the cross-sectional shape of the struts.

11. An impingement-type separator for the removal of finely dividedmatter from a gas stream comprising a '7 casing having a gas inlet endand a gas dischargeend; a module assembly insertabie into and removablefrom said easing, said module comprising a series of internal struts'andseparate strut retainer means, said struts having a curvedcross-sectional shape and being positioned normal to the flow directionof said gas stream at substantially uniform intervals across thecross-sectional area of the module and along the longitudinal flow pathof said gas stream so that matter entrained in the gas streams isseparated therefrom by impingement against such struts, said strutretainer means being positioned at each end of the struts and havingrecesses to hold opposite ends of the struts in position, and beingarranged and constructed with pairs of recesses in adjacent retainersconmeeting with each other and contoured to each receive a section of:the strut end.

References Cited in the file of this patent UNITED STATES PATENTS718,805 Watts Jan. 20, 1903 1,016,741 Fritz Feb. 6, 1912 1,336,870 TracyApr' 13, 1920 1,521,348 Ambruster Dec. 30, 1924 1,807,983 Hegan et al.June 2, 1931 1,876,406 Feuillee Sept. 6, 1932 1,886,927 Williams Nov. 8,1932 2,078,558 -B-rell Apr. 27, 1937 2,785,768 Gauchard Mar. 19, 1957

